Fuel-feeding mechanism for coal-dust furnaces



Mar. 27, 1923. 1,449,633

J; TAYLOR FUEL FEEDING MECHANISM FOR COAL DUST FURNACES Filed June 13,1921 4 sheets-sheet l 5" '22 1| nn L HH ll w 1 /0 E f /5 I lIlln- I I l/VVENTOR A TTORNEY Mar. 27, 1923. 1,449,633

. J. TAYLOR FUEL FEEDING MECHANISM FOR COAL DUST FURNACES Filed June 133, 1921 4 sheets-sheet 2 INVENTOR ATTORN EY Mar. 27, 1923. 1,449,633

, J. TAYLOR FUEL FEEDING MECHANISM FOR COAL DUST FURNACES Filed June 15, 1921 4 sheets-sheet 5 Maw.

A TTORNEY Mar. 27, 1923. 1,449,633

J. TAYLOR FUEL FEEDING MECHANISM FOR COAL DUST FURNACES v Filed June 13, 1921 L sheets-sheet 4 INVENTOR A TTORNE Y Patented Mar. 27, 1923.

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JOHN TAYLOR, 0F SALT LAKE CITY, UTAH.

FUEL-FEEDING MECHANISM FOR COAL-DUST FURNACES.

Application filed June 13,

tain new and useful Improvements in Fuel- Feeding Mechanism for Coal-Dust Furnaces, of which the following is a specifica tion.

This invention relates to fuel feeding mechanism for coal dust furnaces. A Patent No. 1,373,77 6 of April 5, 1921, was granted to me for mechanism of the general character of that shown in this application. However, as this description proceeds, it will be seen that many refinements and improvements over the structure of the aforesaid patent are embodied in this my improved apparatus.

The invention includes among its objects the provision of a simple and economical construction by means of which fine fuel, such as powdered coal may be fed, in suspension, along witha column of air, into a fuel supply pipe leading to the combustion chamber o a furnace (not shown). Furnaces for burning fine fuel in suspension are well known in the art and this application relates particularly to the means for feeding such ne fuel rather than to any particular type of furnace, the device being applicable to furnaces of different kinds. 7

It is also an object of the invention to provide means for uniformly crushing the coal to insure against particles of more than a given size being fed through the blast fans, and to vary the degreer-of fineness ofthe coal at will,.and also to provide means for varying the proportion between the coal dust and the air.

Further objects and advantages of the invention will be set forth in the detailed description which follows.

In the accompanying drawings:

Fig. 1 is a plan view of that part of the feeding mechanism which underlies the coal bin;

Fig. 2 is a side elevation of the construc-- tion illustrated in Fig. 1;

Fig. 3 is a plan view of the lower part of the mechanism illustrated in Fig. 2;

Fig. 4 is a detail view of a spiral conveyor hereinafter described;

1921. Serial No. 477,207.

Fig. 5 is a side elevation of the fuel feeding mechanism with the coalbin in section;

Fig. 6 is a view partly in section and partly in plan of the fan end of the feeding mech anism;

Fig. 7 is a sectional view upon line 7-7 of Fig. 8;

Fig. 8 is a sectional view upon line 8-8 of Fig. 7; and

Fig. 9 1s a sectional view illustrating a two stage fan.

' Like numerals designate corresponding parts throughout the several figures of the drawings.

In the drawings 5 designates a coal bin having an opening 6 in its bottom which registers with an opening 7 formed in the upper half of a casing 8. This casing is provided with perforated ears 9 through which bolts 10 may be passed for the purpose ofbolting the casing to the under side of the coal bin. A manually operable slide 11 is adapted'to restrict the size of the opening 7 to any desired extent, or to completely close the same, at will. This slide is operable in a channel 12 and moves beneath a keeper 13, see Fig. 1. of the casing is secured to the upper half thereof by nuts 14 which may be threaded upon the lower ends of the bolts 10, or may be threaded upon separate screws 15, it being apparent that many ways of securing these parts together! will readily suggest themselves to the mechanic. The interior of the casing 8 is spirally grooved or rifled, as indicated at 16, and a spiral conveyor 17, see Fig. 4., operates in this casing. This spiral conveyor differs radically from ordinary spiral conveyors, in that it comprises two distinct helical grooves, one of which increases in pitch from the front to the rear end of the conveyor and the other of which decreases in pitch. The result is that one roove, v1z,-groove 18 1s of cons1derable capacity at the start and gradually decreases in capacity toward the right until it merges into nothingness at about the point 18 The other groove,- which is substantially the reverse of the first, begins at 19 and gradually increases in capacity formin a groove 19, which extends to the terminal orright hand end of the conveyor and beyond the point where the groove 18 vanishes. Furcasing 8.

'thermore, it may here be noted that the conveyor as a whole flares, being of larger diameter at its right hand end than at its left hand end, and the same thing is true with respect to the interior of the chamber 8, as will be apparent from a careful inspection of Fig. 3. It is the action of the rib 18 acting in conjunction with the grooves 16 which acts to grind the coal to a uniform degree of fineness, and this degree of fineness may be varied by shifting the conveyor endwise in the casing 8. This is accomplished by 'means of a rod 20, which is pivoted at 21 to a lever 22. The lever 22 is pivoted, in turnat 23 toa bracket 24 of the The lever 22 carries a pin which enters an annular groove 26, see Fig. 4, in the shaft of the conveyor. Thus endwise movement of the rod 20 will shift the conveyor endwise without interfering with the rotative movement of the conveyor. The right hand end of the rod 20 carries a pin 21 the lower end of which is adapted to be inserted in any one v of the openings 22 by means of which the conveyor may be held in its adjusted position. .A coal delivery pipe 23 leads from the left hand end of the casing 8 and coal is fed through this pipe by the conveyor 17, the coal initially entering the grooves 18 and remaining trapped therein until it is crushed to such a degree of fineness that it will pass about or beneath the rib '18 from the groove 18 to the groove In other words, only coal which has been crushed to the desired degree of fineness can enter the groove 19, and it is this groove which extends to the delivery point 24, where the finely powdered fuel is discharged into-a downwardly directed channel 25 (see Fig. 7).

The right hand end of the conveyor shaft 17 carries a toothed wheel 26*, and this toothed wheel is engaged by a worm 27 that is mounted upon a transverse shaft 28. The shaft 28 carries a large pulley 29 that is driven by a belt 30 and a motor shaft 31.

" The belt may be tightened at any time by merely adjusting the housing 32, shaft 28 and pulley 29 toward the right by means of the screws 33 slots '34 and screw 34. The motor 35 of which 31 constitutes the main shaft is concentrically disposed with relat1on to a fan casing 36. The fan 37 is r mounted directly upon the motor shaft and a fuel feeding wheel 38 is likewise mounted directly upon said shaft and controls the passage of fuel from the channel 25' into the fan casing proper. A fuel discharge pipe 39- leads from the fan casing to any desired polnt of discharge, such, for example, as the combustion chamber of a furna e The fan receives its air supply through an opening 4Q that is controlled by a door 41. This (1061' is hinged at 42 and a pivoted lever 43 carried by said door is operated by a chain 44. When the chain is slackened or lowered, the weight 45 carried by the lever acts to open thel door. In orderto insure that this door will always be open when the motor is started, I may associate with the chain 44 a controlling switch that is included in the motor line. Such an arrangement is diagrammatically shown in Fig. 8. Wires 46 and 47 designate the motor leads having a break included therein which may be closed by bringing the inner end 49 of a- 39 through the combustion chamber, when the fuel feeding apparatus is idle and which leakage of air would otherwise undesirably cool off the combustion chamber. 7, I, .In Fig. 91 have illustrated a two stage fan which may be employed advantageously where high pressure is desired. The parts, in the main, are the same as those employed in Fig. 8, and the same reference characters have been applied. The structure differs from that illustrated in ,Fig. 8 in that two sets of blades 37*, 37", have been illustrated constituting, a two stage fan. Two separate outlets 55 and 56 are provided "and if the outlet 55 be separately connected to a combustion chamber and if the outlet 56 be likewise connected to said combustion chamber, it is manifest that pure air free of fuel in suspension may be delivered to the combustion chamber from the outlet 55 or that by closing the outlet 55 all of the air may be delivered through 56, as high pressure air, with the fuel in suspension thereln.

Whether a single stage fan, such as is illustrated in Fig. 8, be employed or whether a two stage fan, such as is illustrated in Fig. 9, be employed, it is desirable to prevent air from leaking back past the conveyor to the coal bin, since this air would support combustion if a fire got started in the coal bin.

Therefore, I provide a port 25 through which air may enter and pass downwardly past the fuel feeding wheel settin up a circulation, as indicated by arrow to draw air away from conveyor 17. In Fig. 9 a port 57 leads from a point adjacent the discharge end of the conveyor around to the intake side of the fan and this prevents the passage of air back past the conveyor into the coal bin.

It is to be understood that the invention is not limited to the precise construction set forth butljthat it includes within its purview whatever changes fairly come Within either the terms or the spirit of the appended claims.

Having despribed my invention, What I claim is 2 1. In a device of thecharacter described the combination with a coal bin, of a blast apparatus and a fuel feeding and comminuting means extending between the coal bin and the blast apparatus and receiving the coal from the coal bin and delivering it to the blast apparatus to be discharged by the latte'r into a furnace, said fuel feeding and comminuting means comprising a casing connected at one end to the coal bin andat the other end to the blast apparatus and a spiral conveyor mounted for rotation in said casing, said conveyor having a fuel receiving groove and a;,fuel discharge groove'formed therein, said grooves interlapping axially, and said grooves being separated by spiral walls which areso proportioned and arranged with respect to the casing as to permit the passage of powdered fuel from the fuel receiving'groove to the fuel discharge groove when said fuel has been crushed to av predetermined degree of fineness.

2. A structure as, recited in claim 1 wherein. said spiral conveypr flares in its length and means for adjusting it lengthwise in combination with the casing in which it operates, such lengthwise adjustment varying I the spacing-of the periphery of the conveyor from the Wall of its casing to determine the degree of fineness to which the fuel must be crushed before it pa ses from the fuelreceiving groove to the d livery groove.

- 3. The combinati n with a coal bin, of a caslng having a receiving end and a discharge end, said casing flaring from its receiving end to its discharge end and said casing having a spiral groove formed in it; Walls which gradually diminishes in dept from the receiving end of the casing toward the discharge end thereof, and a spiral conveyor mounted for rotation in said casing, said conveyor flaring toward the discharge end of said casing, said conveyor having two spiral grooves formed therein which overlap axially, one of said grooves constituting a receiving groove which is of large capacity at the receiving end of the conveyor and d1- minishes in capacity toward the discharge end of'the conveyor and the other of said grooves being of small capacity at that end of the conveyor toward the coal bin andjncreasing in capacity toward the discharge end of the casing the last named groove extending further along the conveyor than the first named groove.

In testimony whereof I afiix my signature in the presence of two witnesses.

' I JOHN TAYLOR. Witnesses:

ROBERT L. Juno, 3 BEVERLY S. CLENDENIN, 

